ACE2 and COVID-19: The discovery of ACE2 as the receptor of SARS-CoV and now SARS-CoV-2 has led to a debate regarding the role of ACE2 in COVID-19: (i) whether ACE2 upregulation enhances SARS-CoV-2 infectivity and can be related to more severe cases and (ii) whether SARS-CoV-2 binding reduces ACE2 bioavailability, which causes impairment of RAS that is associated with a more severe disease.